I may have found the problem with the major issue im having...I didn't think of this earlier and now im kicking myself for not trying it...The BF3 beta nvidia drivers breaks the game for me.

My brother has an identical rig to mine cept the chassis, he plays bf3 beta and tells me he gets no stuttering when moving mouse the only difference is that he is running the whql drivers not the bf3 beta..soo uninstalling beta drivers and reverting bk, will update when done.

I think I noticed this jerkiness too once I installed the beta drivers; rolling back to 280.26 now and I'll see if there's a difference again. We both have 200 series so that would make sense...

edit: yeah definitely a lot smoother with 280.26. FRAPS doesn't say the FPS is any different but it definitely looks much smoother